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Birch - No Bueno
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Dr. Delam



Joined: 01 Feb 2007
Posts: 371
Location: Truckee

PostPosted: Mon Oct 12, 2015 12:17 am    Post subject: Birch - No Bueno Reply with quote

I got a good deal on some birch and thought I would try it for some sidewalls. While profiling my cores through my planer I was getting a lot of tearout and lost a huge chunk near the end and almost had to scrap the core. Fortunately it was just barely in the cutoff area.

I thought it might be due to dulling planer blades but after doing some research it is prone to tearout.

I will be really pissed if I get more tearout when I profile the sidewalls. Maybe I'll have better luck though with the different grain orientation. Anybody else experience this with birch?
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skidesmond



Joined: 07 Apr 2009
Posts: 2277
Location: Western Mass, USA

PostPosted: Mon Oct 12, 2015 5:33 am    Post subject: Reply with quote

I haven't used birch. The tear out could be from the grain orientation. You can also try using a spray bottle of water and spray the core lightly as you're profiling and take shallow passes with the planer, that helps.
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Dr. Delam



Joined: 01 Feb 2007
Posts: 371
Location: Truckee

PostPosted: Mon Oct 12, 2015 11:42 pm    Post subject: Reply with quote

I decided I don't want to risk rabbeting the sidewalls so I am going to use a cork layer between the edges and just keep the cores totally flat on the bottom. I've been wanting to try some cork for dampening so this is the perfect opportunity.

The sidewall profiling will probably be ok but I think I am going to do it in two steps to achieve the desired angle just to be safe.
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skidesmond



Joined: 07 Apr 2009
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Location: Western Mass, USA

PostPosted: Tue Oct 13, 2015 3:47 am    Post subject: Reply with quote

I use cork between the edges. I just received my order the other day. I never did damping tests, it must give some damping I would think. I use it to fill the space between the edges and it's a perfect fit, .8mm thick.
http://www.corkstore.com/Products/Cork-Sheets-CR117/CR117-Cork-Sheet-0-8mm
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vinman



Joined: 09 Nov 2007
Posts: 1293
Location: The tin foil isle

PostPosted: Tue Oct 13, 2015 3:20 pm    Post subject: Reply with quote

DD or SD does the cork soak up a lot of resin? How do the bases come out as far as flatness goes?
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MontuckyMadman



Joined: 20 Jun 2008
Posts: 2341

PostPosted: Tue Oct 13, 2015 5:34 pm    Post subject: Reply with quote

My cork tests did not result well. My edges were railed and bases concave as well as edge tine translation through the base. The cork is pretty hydrophibic so extra resin wasnt an issue. I still have to rabbit. I think a less compressive material might be better.
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skidesmond



Joined: 07 Apr 2009
Posts: 2277
Location: Western Mass, USA

PostPosted: Wed Oct 14, 2015 3:23 am    Post subject: Reply with quote

I've had good results so far. I don't rabbet the core. The cork does not soak up resin and bonds well. I press at 40-45psi. MM you're pressing at a much higher psi, right?

I've made tests using .8mm cork and 1.5mm poplar veneer in a skateboard style layup and then profiled it using a planer. I was expecting the cork to tear out or rip/shred but it didn't, it planed just as smoothly as the poplar. Of course the sample layup (6 veneer layers, 5 cork layers) was a bit flimsy. You'd have to reinforce with a heavy weight triax FG or CF.

Maybe I should start a thread on cork.... :-)
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chrismp



Joined: 13 Feb 2009
Posts: 1241
Location: Vienna, Austria

PostPosted: Wed Oct 14, 2015 11:33 am    Post subject: Reply with quote

I guess the combo of heat and higher pressure is what makes the difference.

Do you put the cork directly onto the base or on top of the bottom layers of fg? I'm asking because adding the cork below the fg would IMO just add weight without increasing stiffness. Putting it on top of the fg would allow to make the core thinner and at least not add any weight as the layers of fg are further apart which would increase stiffness.
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skidesmond



Joined: 07 Apr 2009
Posts: 2277
Location: Western Mass, USA

PostPosted: Wed Oct 14, 2015 1:21 pm    Post subject: Reply with quote

chrismp wrote:
I guess the combo of heat and higher pressure is what makes the difference.

Do you put the cork directly onto the base or on top of the bottom layers of fg? I'm asking because adding the cork below the fg would IMO just add weight without increasing stiffness. Putting it on top of the fg would allow to make the core thinner and at least not add any weight as the layers of fg are further apart which would increase stiffness.


I put it right on the base between the edges. It's cork so you're not adding a lot of weight. I just weighed a sheet of 24x36in cork, about 3 oz. You'd use less than 1 sheet for a pair of skis.
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falls



Joined: 27 Oct 2009
Posts: 1426
Location: Wangaratta, Australia

PostPosted: Wed Oct 14, 2015 2:07 pm    Post subject: Reply with quote

Definitely do your sidewall bevel in multiple passes.
With bamboo I used to go straight for 22 degrees and tear out strips of bamboo and have to fill with epoxy. Now I have the tilt base router I do 7.5, then 15 then 22.5 if I am going that far. So far (touch wood) I haven't had any problems with tearing out with this new approach.
Only thing is you multiply the chances of stuffing up by 2 or three because you have to do more passes.
Sidewall bevel - easily the most worrying part of construction!
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Dr. Delam



Joined: 01 Feb 2007
Posts: 371
Location: Truckee

PostPosted: Wed Oct 14, 2015 10:29 pm    Post subject: Reply with quote

I've never had a problem with tearout on bamboo while planing or profiling the sidewalls. I only go to 7 degrees at the most when profiling though.

Falls, what tilt base router do you run? It's probably about time I buy one instead of switching out the base on mine all the time.
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Dream



Joined: 15 Sep 2014
Posts: 32

PostPosted: Thu Oct 15, 2015 7:23 am    Post subject: Reply with quote

+1 on sidewall beveling being a pretty tense process!!
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skidesmond



Joined: 07 Apr 2009
Posts: 2277
Location: Western Mass, USA

PostPosted: Thu Oct 15, 2015 2:30 pm    Post subject: Reply with quote

I agree about the sidewall. At that point you're nearing the end and if tear out occurs or router slips.... My vocabulary slims down to a few words :-)
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MontuckyMadman



Joined: 20 Jun 2008
Posts: 2341

PostPosted: Thu Oct 15, 2015 5:25 pm    Post subject: Reply with quote

Taking it in 2 or 3 passes is the no worry way and a tilt base is by far the easiest.
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falls



Joined: 27 Oct 2009
Posts: 1426
Location: Wangaratta, Australia

PostPosted: Fri Oct 16, 2015 3:51 am    Post subject: Reply with quote

I have a Bosch. From their professional series. 1/4 inch collet. Has been a great tool. I use it for base cut out as well.
I think they call it a Bosch colt in the US.

http://www.boschtools.com/Products/Tools/Pages/BoschProductDetail.aspx?pid=PR20EVSNK
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